That is a dynamic library file. A shared part of a program found in the Windows system directory, this one is used to work with database saving...something very common. It's also quite common for DLL files, particularly on Window98, to get misplaced. I googled the file:
http://www.dll-files.com/dllindex/dll-files.shtml?oleaut32
adding this file to C:\Windows\System will solve the problem...howver there may be more problems, or more libraries you need.
BTW, It is NOT any more complicated reinstalling Windows 98 then it is reinstalling Windows XP. You just need the disk. Depending on the age of the computer, (if you cannot boot off a CD) you may also need a Windows 98 Boot floopy...these come with the Window 98 CD, or can be made easily by right-clicking the Disk icon in Explorer/My Computer. Remember to FORMAT the C:\ after booting from the floppy, if you do it that way.
Windows 98 is notorious for being unstable. Back in those days I rmember I had to reformat C: and reinstall Windows 98 every couple months just to keep it running smoothly. If you can get your hands on it, Windows NT SP6, or Windows 2000 (The professional network versions of the OS) are FAR more stable than 98 or ME.